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Poster: HappySwordsman Date: Aug 1, 2012 1:04am
Forum: classic_tv Subject: Re: To The_Emperor: frame rates

That's at least partially wrong. I've bought many NTSC DVDs and they are all 29.9 frames per a second. All the PAL DVDs I've bought are 25 frames per a second.

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Poster: Moongleam Date: Aug 1, 2012 2:45am
Forum: classic_tv Subject: Re: To The_Emperor: frame rates

Many NTSC DVDs switch back and forth between 30000/1001 fps and 24000/1001 fps, with most of the movie being 24 fps. (I guess the 30 fps bits occur at scene changes, for some reason.)

For example, mplayer shows this about "Conspiracy Theory":

VIDEO: MPEG2 720x480 (aspect 2) 29.970 fps 7500.0 kbps (937.5 kbyte/s)
==========================================================================
Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
Selected video codec: [ffmpeg2] vfm: ffmpeg (FFmpeg MPEG-2)
==========================================================================
Audio: no sound
Starting playback...
Movie-Aspect is 1.33:1 - prescaling to correct movie aspect.
VO: [null] 720x480 => 720x540 Planar YV12
[mpeg2video @ 01104214]ac-tex damaged at 6 8
[mpeg2video @ 01104214]Warning MVs not available
[mpeg2video @ 01104214]concealing 990 DC, 990 AC, 990 MV errors

demux_mpg: 24000/1001fps progressive NTSC content detected, switching framerate.


demux_mpg: 30000/1001fps NTSC content detected, switching framerate.
Warning! FPS changed 23.976 -> 29.970 (-5.994005) [4]

demux_mpg: 24000/1001fps progressive NTSC content detected, switching framerate.


demux_mpg: 30000/1001fps NTSC content detected, switching framerate.
Warning! FPS changed 23.976 -> 29.970 (-5.994005) [4]

demux_mpg: 24000/1001fps progressive NTSC content detected, switching framerate.


demux_mpg: 30000/1001fps NTSC content detected, switching framerate.
Warning! FPS changed 23.976 -> 29.970 (-5.994005) [4]

demux_mpg: 24000/1001fps progressive NTSC content detected, switching framerate.


demux_mpg: 30000/1001fps NTSC content detected, switching framerate.
Warning! FPS changed 23.976 -> 29.970 (-5.994005) [4]

demux_mpg: 24000/1001fps progressive NTSC content detected, switching framerate.


demux_mpg: 30000/1001fps NTSC content detected, switching framerate.
Warning! FPS changed 23.976 -> 29.970 (-5.994005) [4]

demux_mpg: 24000/1001fps progressive NTSC content detected, switching framerate.


demux_mpg: 30000/1001fps NTSC content detected, switching framerate.
Warning! FPS changed 23.976 -> 29.970 (-5.994005) [4]

demux_mpg: 24000/1001fps progressive NTSC content detected, switching framerate.

... and so on.


As for converting a video from 30 fps telecined to 24 fps progressive, I do it in order to reduce the required bitrate. However, pullup filters can't do a perfect job when the video isn't in pristine condition, and this seems to result in some jerky motion (which is probably to be found in "Man against Crime: Murder Mountain").

This post was modified by Moongleam on 2012-08-01 09:37:18

This post was modified by Moongleam on 2012-08-01 09:45:15

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Poster: billymays55 Date: Aug 1, 2012 10:26pm
Forum: classic_tv Subject: Re: To The_Emperor: frame rates

I have no idea what "Conspiracy Theory" is??

here is a good starter I found that explains it way better then i can

NTSC film vs. NTSC video
There are two types of NTSC content: NTSC film, and NTSC video. Video is generally interlaced while film is usually progressive.

NTSC video is 30fps. This is what you get on TV.

Most movies aren't recorded at 30fps, and neither are most modern TV shows. They're done at film speed: 24fps.

24fps or 23.976? 30fps or 29.976?
This guide has used 24fps for NTSC film and 30fps for NTSC video. This is because it's simpler and takes less time to write. However, it's not really precise.

Back in the day, NTSC TV video was indeed 30fps. However, video hasn't "really" been 30fps since color TV broadcasts started. Before them it was 30000 frames for every 1000 seconds. But to accommodate the extra color information, the rate was very slightly dropped by stretching the frames to cover an extra second for every 1000 seconds, making it 30000/1001.

30fps == 30000/1001 == 29.97fps

24fps == 24000/1001 == 23.976fps

that makes it pretty simple and easy to understand but I also noitced your mpeg stream has multiple errors

mpeg2video @ 01104214]ac-tex damaged at 6 8
[mpeg2video @ 01104214]Warning MVs not available
[mpeg2video @ 01104214]concealing 990 DC, 990 AC, 990 MV errors

that could be causing some problems as well? As for the reason that your program is not converting your hard-telecine back to 23.976 during fades is it can't see the 3:2 pattern in the fades, so it thinks it is plain NTSC video which cannot be converted to 23.976 so it leaves your framerate at 29.976 which would obviously cause jerky playback.

The best program there is to make nice xvid or divx conversions of mpegs or dvds is Auto Gordian Knot, it is all pretty automatic and it figures out if it is NTSC video or NTSC film as it does a 2 pass encoding first pass to configure frame rate, also does noise reduction, color correction etc

It never gives you jerky playback results and makes a really nice encode

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Poster: HappySwordsman Date: Aug 1, 2012 2:52am
Forum: classic_tv Subject: Re: To The_Emperor: frame rates

OK, thanks for the info ("The Trouble with Father" also has jerky picture quality).